Sample- Paper- Class – X Subject –Physics Light: Reflection and Refraction
Very short Answer 1. What is radius of plane mirror? 2. What is angle of reflection for a ray falling normally on a plane mirror? 3. Why do we use convex surface for side view mirror? 4. Can a virtual image be photographed? 5. What is the power of a plane mirror? 6. When the angle of incidence is 90 deg., what is the angle of refraction? 7. What is the value of refractive index of air? 8. What is the magnification produced by a plane mirror? 9. Define power. Give its S.I unit? 10. What is power of sunglass? Download full paper: Reflection_and_refraction_test_paper-1 You may also like 10th Light – Reflection and Refraction Key concepts and terms X Physics Reflection and Refraction Solved questions 10th_physics_ch._light__reflection_and_refraction_ncert_solution
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GIST OF THE CHAPTER Light Refraction and Refraction
1. The first theory of light was put forward by Newton. This theory treats light as a particle called corpuscle. 2. We can say that light propagates as a wave and is emitted and absorbed as a particle. 3. One may regard light as having dual nature. 4. Maxwell proved that light has wave nature; it is an electromagnetic transverse wave, which does not require medium to propagate. 5. The speed of light in air is a universal constant. It has a value of 3x108m/s. 6. Light gets reflected when it falls on polished surface; like mirror. 7. Light suffers refraction when it travels from one medium to another. 8. There is a change in the wavelength of light when it moves from one medium to another. 9. The image is unmagnified, virtual and erect in a plane mirror. 10 Focal length of a plane mirror is infinity. 11. Power of a plane mirror is zero.' 12. It should be noted that, if the spherical lenses are surrounded by a material with a refractive index greater than that of the lens, the convex lens gets converted into a concave lens or vice-versa. FORMULAE f = R/2 1 / v + 1 / u = 1 / f = 2 /R M = h2 /h1 = -v/u n = c/v 1n2 = 1/2n1 1n2 = n2/n1= sin i/sin r a n w = x/y 1/v –1/u = 1/f m =I/O = h2 /h1 = v/u P= 1/f metre P = p1 + p2 + p3 + ……. VERY SHORT QUESTIONS CARRYING 1 MARK EACH. 1. Out of convex mirror and concave mirror, whose focus is situated behind the mirror? Ans: The focus of convex mirror is situated behind it. 2. For what position of an object, a concave mirror forms an enlarged virtual image? Ans: Object between pole (P) and focus (F) of the concave mirror. 3. If the focal length of a concave mirror is 25cm. What is its radius of curvature? Ans: Focal length = Radius of curvature / 2 25 = R / 2 R = 25 X 2 = 50cm. 4. A ray of light falls on a mirror normally. What are the values of angle of incidence and the angle of reflection? Ans: Both angle of incidence and the angle of reflection are zero. 5. What is the focal length of a plane mirror? Ans: Infinite. 6. Which spherical mirror is called a divergent mirror? Ans: A convex mirror is called a divergent mirror. 7. What is the angle of incidence, when a ray of light falls on the spherical mirror from its centre of curvature? Ans: The angle of incidence is zero, when a ray of light falls on the spherical mirror from its centre of curvature. 8. Name the type of mirror that always forms a virtual image for a real object? Ans: Convex Mirror. 9. State the relation between radius of curvature and focal length of spherical mirrors. Ans: Radius of curvature = 2 X focal length. R = 2f. 10. Which of the two is a diverging lens? Convex lens (or) Concave lens. Ans: Concave lens. 11. If an object is placed at a distance of 10cm in front of a plane mirror, how far would it be from its image? Ans: The object would be at a distance of 20cm from its image. 12. Name the physical quantity which remains the same when light goes from one medium to another? Ans: Frequency of light. 13. Define power of a lens. Ans: The reciprocal of the focal length of the lens is called power of a lens. P = 1/f 14. Calculate the power of a convex lens of focal length 25cm? Ans: Focal length f = 25cm. Power = 1/.25 = 100/25 = +4D. 15. Name the phenomenon responsible for the following affect. Ans: When we sit in front of a plane mirror and write with our right hand, it appears in the mirror that we are writing with the left hand.Ans: Lateral Inversion 16. Define Refractive Index Ans: It is the ratio of speed of light in vacuum to the speed of light in medium is called Refractive index. 17. Why is the convex lens also known as a converging lens? Ans: A convex lens is also known as a converging lens because it converges a parallel beam of light raying passing through it. 18. Give the ratio of velocities of two light waves travelling is vacuum and having wave lengths 4000A and 8000A. Ans: In Vacuum, light of all the wave lengths travel with the same velocity i.e. 3 X 108 m/sec. 19. For what angle of incidence, the lateral shift produced by parallel sided glass plate is zero? Ans: For i = 0. 20. What are the factors on which the lateral shift depends? Ans: Thickness of the refracting medium, angle of incidence and its refractive index. 21. What is the power of a plane glass plate? Ans: Zero. 22. An object is placed at the focus of a concave lens. Where will its image be formed? Ans: The rays will appear to come from infinity. Therefore, a virtual image will be formed at infinity. 23. What is the unit of power of a lens? Ans: Dioptre. 24. Why the stars appear to twinkle? Ans: The twinkling of a star is due to the atmospheric refraction of star’s light. 25. What is the value of refractive index of air? Ans: One More study material visit : 10th Science - Light Refraction and Refraction10th Light – Reflection and Refraction Key concepts and terms X Physics Reflection and Refraction Solved questions-1 Point to remember:-
1. Species maintain continuity by reproduction. 2. Variation in different degrees occur. 3. Variants have unequal chances of survival. 4. In sexually reproducing individuals, for the same trait genes have two copies. Unidentical copies bear dominant and recessive nature. 5. Traits separately inherited, yields new combinations of traits in progeny. 6. The sex of human progeny is determined by the sex chromosomes inherited from father. 7. Variation in combination with geographical isolation might lead to speciation. 8. Evolutionary relationship among living organisms become visible in hierarchy of classification. 9. Study of living forms as well as dead remains of organisms emerges as evolutionary scene. 10. DNA changes accumulated over a time span has resulted in evolution of complex organs like eye as exhibited by structure of eye in different animals. 11. Features like feathers have evolved as a function of change in allocated task. 12. Evolution is not progress from lower to higher forms. 1 mark questions :- 1. Which of the two exhibit greater variation : asexual or sexual reproduction? 2. Why all the variants don't have equal chances of surviving? 3. What is heredity? 4. At which place on earth did humans appeared first? 5. Give the name of plant studied by Mendel? 6. Name the acid which is information source for making proteins in cells. 7. What is the chemical nature of enzymes? 8. Define gene.9. Which one of the two is shorter in length 'X' or 'Y'? Chapter - 9 Heredity and Evolution read more............ Points to remember:-
1. Reproduction is essential for continuity of living organisms. 2. It involves creation of a DNA copy along with the formation of additional cellular apparatus during cell division. 3. Basically it is of two types – Asexual and sexual. Some plants like Rose and Banana are prolifrated by vagetative propogation. 4. There are examples of asexual reproduction where new generation arises from a single cell or single individual as in fission, fragmentation, regeneration, budding, spore formation. 5. Sexual reproduction involves two individuals to produce off spring. 6. Variation occurs due to DNA copying mechanism and sexual reproduction. 7. Reproduction in flowering plants involve transfer of pollen grains from anther to stigma – pollination. Gametes fertilize to form zygote. 8. Changes occur in boys and girls at puberty, beard and moustache in boys and growth in breast region in girls apart from other changes. These changes indicate sexual maturation and biological preparedness for reproduction. 9. Sexual reproduction takes place by fusion of both male and female gametes resulting in the formation of zygote which gives rise to offspring. 10. Awareness regarding family planning and sex related communicable diseases (STDs) help individual to maintain normal reproductive health. 11. Condoms, oral pills, copper T are some of the contraceptives to avoid pregnancy. 1 mark questions :- 1. Why simply copying of DNA in a dividing cells not enough to maintain continuity of life? 2. How does plasmodium undergo fission? 3. How spirogyra reproduces by fragmentation? Full Study Chapter - 8 How Do Organisms Reproduce Click here |
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